Remove unreachable blocks before splitting a coroutine.

The suspend-crossing algorithm is not correct in the presence of uses
that cannot be reached on some successor path from their defs.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@368796 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGenCoroutines/coro-retcon-unreachable.ll b/test/CodeGenCoroutines/coro-retcon-unreachable.ll
new file mode 100644 (file)
index 0000000..27ee2fd
--- /dev/null
+++ b/test/CodeGenCoroutines/coro-retcon-unreachable.ll
@@ -0,0 +1,46 @@
+; RUN: opt < %s -coro-early -coro-split -S | FileCheck %s
+target datalayout = "E-p:64:64"
+
+%swift.type = type { i64 }
+%swift.opaque = type opaque
+%T4red215EmptyCollectionV = type opaque
+%TSi = type <{ i64 }>
+
+define hidden swiftcc { i8*, %swift.opaque* } @no_suspends(i8* %buffer, i64 %arg) #1 {
+  %id = call token @llvm.coro.id.retcon.once(i32 32, i32 8, i8* %buffer, i8* bitcast (void (i8*, i1)* @prototype to i8*), i8* bitcast (i8* (i64)* @malloc to i8*), i8* bitcast (void (i8*)* @free to i8*))
+  %begin = call i8* @llvm.coro.begin(token %id, i8* null)
+  call void @print(i64 %arg)
+  call void @llvm.trap()
+  unreachable
+
+bb1:
+  call void @print(i64 %arg)
+  call i1 @llvm.coro.end(i8* %begin, i1 false)
+  unreachable
+}
+; CHECK-LABEL: define hidden swiftcc { i8*, %swift.opaque* } @no_suspends(
+; CHECK:         call token @llvm.coro.id.retcon.once
+; CHECK-NEXT:    call void @print(i64 %arg)
+; CHECK-NEXT:    call void @llvm.trap()
+; CHECK-NEXT:    unreachable
+
+declare swiftcc void @prototype(i8* noalias dereferenceable(32), i1)
+declare void @print(i64)
+
+declare noalias i8* @malloc(i64) #5
+declare void @free(i8* nocapture) #5
+
+declare token @llvm.coro.id.retcon.once(i32, i32, i8*, i8*, i8*, i8*) #5
+declare i8* @llvm.coro.begin(token, i8* writeonly) #5
+declare token @llvm.coro.alloca.alloc.i64(i64, i32) #5
+declare i8* @llvm.coro.alloca.get(token) #5
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #6
+declare i1 @llvm.coro.suspend.retcon.i1(...) #5
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #6
+declare void @llvm.coro.alloca.free(token) #5
+declare i1 @llvm.coro.end(i8*, i1) #5
+
+declare void @llvm.trap()
+
+attributes #1 = { noreturn nounwind }
+attributes #5 = { nounwind }